/**
 * Stream Event Types
 *
 * Events emitted during real-time conversation streaming.
 * Supports both text deltas (character-by-character) and status updates
 * (metadata changes like tool execution status).
 *
 * These events allow UIs to:
 * - Show typing animations for assistant text
 * - Display thinking in real-time
 * - Update tool/subagent execution status
 * - Track progress of long-running operations
 */
import type { ConversationBlock } from './blocks.js';
/**
 * Block Start Event
 *
 * Emitted when a new block begins. The block may be incomplete
 * (e.g., AssistantTextBlock with empty content that will be filled via deltas).
 *
 * Use cases:
 * - AssistantTextBlock starts (content: "")
 * - ThinkingBlock starts (content: "")
 * - ToolUseBlock created (may have partial input)
 */
export interface BlockStartEvent {
    type: 'block_start';
    /**
     * The block that's starting (may be partial/incomplete)
     */
    block: ConversationBlock;
    /**
     * Which conversation thread this belongs to
     */
    conversationId: 'main' | string;
}
/**
 * Text Delta Event
 *
 * Emitted when text content is streaming in character-by-character.
 * Only applies to blocks with text content (AssistantText, Thinking).
 *
 * The UI should append this delta to the existing block content.
 */
export interface TextDeltaEvent {
    type: 'text_delta';
    /**
     * ID of the block being updated
     */
    blockId: string;
    /**
     * Text to append to the block's content
     */
    delta: string;
    /**
     * Which conversation thread this belongs to
     */
    conversationId: 'main' | string;
}
/**
 * Block Update Event
 *
 * Emitted when a block's metadata/status changes (not text content).
 *
 * Use cases:
 * - ToolUseBlock status: pending � running � success
 * - SubagentBlock status: pending � running � success
 * - SubagentBlock output populated when complete
 * - Model information added to AssistantTextBlock
 */
export interface BlockUpdateEvent {
    type: 'block_update';
    /**
     * ID of the block being updated
     */
    blockId: string;
    /**
     * Partial updates to apply to the block
     * Only non-content fields should be updated here
     */
    updates: Partial<ConversationBlock>;
    /**
     * Which conversation thread this belongs to
     */
    conversationId: 'main' | string;
}
/**
 * Block Complete Event
 *
 * Emitted when a block is finalized and complete.
 *
 * After this event:
 * - No more deltas will be sent for this block
 * - No more updates will be sent for this block
 * - The block is in its final state
 *
 * Use cases:
 * - AssistantTextBlock finished streaming
 * - ThinkingBlock finished streaming
 * - ToolResultBlock received (arrives complete)
 * - UserMessageBlock received (arrives complete)
 * - SystemBlock received (arrives complete)
 */
export interface BlockCompleteEvent {
    type: 'block_complete';
    /**
     * ID of the block that's now complete
     */
    blockId: string;
    /**
     * The complete, final block
     */
    block: ConversationBlock;
    /**
     * Which conversation thread this belongs to
     */
    conversationId: 'main' | string;
}
/**
 * Metadata Update Event
 *
 * Emitted when session-level metadata changes.
 * Not related to a specific block.
 *
 * Use cases:
 * - Token usage updated
 * - Cost updated
 * - Model information
 */
export interface MetadataUpdateEvent {
    type: 'metadata_update';
    /**
     * Metadata updates
     */
    metadata: {
        /**
         * Token usage for the current response
         */
        usage?: {
            inputTokens: number;
            outputTokens: number;
            cacheReadTokens?: number;
            cacheWriteTokens?: number;
            thinkingTokens?: number;
            totalTokens: number;
        };
        /**
         * Cost in USD
         */
        costUSD?: number;
        /**
         * Model being used
         */
        model?: string;
        /**
         * Other arbitrary metadata
         */
        [key: string]: unknown;
    };
    /**
     * Which conversation thread this belongs to
     */
    conversationId: 'main' | string;
}
/**
 * All possible stream event types
 */
export type StreamEvent = BlockStartEvent | TextDeltaEvent | BlockUpdateEvent | BlockCompleteEvent | MetadataUpdateEvent;
export declare function isBlockStartEvent(event: StreamEvent): event is BlockStartEvent;
export declare function isTextDeltaEvent(event: StreamEvent): event is TextDeltaEvent;
export declare function isBlockUpdateEvent(event: StreamEvent): event is BlockUpdateEvent;
export declare function isBlockCompleteEvent(event: StreamEvent): event is BlockCompleteEvent;
export declare function isMetadataUpdateEvent(event: StreamEvent): event is MetadataUpdateEvent;
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